Refrigerator-thermostat.



F. N. ROEHHICH.

REFmGEnAToR THERMOSTAT. APPLICATION FILED OCT. ll, 1912.

1,172,740. Patented Feb.22,1916.

4 SHEETSSHEET I.

F. N. ROEHRICH.

REFRIGERATOR THERMOSTAT.

APPLICATION FILEDVocT. u, 1912.

Patented P91122, 1916.

4 SHEETS-SHEET 2.

| In .m mlm F. N. ROEHRICH. REFRIGERATOR THERMOSTAT.

APPLICATION FILED OCT. H, |912.

Patented Feb. 22, 1916.

4 SHEETS-SHEET 3.

F. N. ROI-IHRICH. REFRIGERATOR THERMOSTAT.

APPLICATION FILED OCT. II. |912.

Patented Feb.22,19'16.

4 SHEETS-SHEET 4.

ZM/Kwam 1J SH01 11 edges. or it may be a Bourdon pressure tube.

t vUNITED STATES PATENT OFFICE.. f

FRANKN. ROEHRICH, 0F JERSEY CITY, NEW JERSEY, ASSIGNOR T0 'GEORGE P. CARROLL, 0F BRIDGEPORT, CONNECTICUT. l 1

Specication of Letters Patent.

i REFRIGERATOR-THERMOSTAT.

Patented Feb. 22, 1916.

Application led October 11, 1912.v Serial No. 725,180.

To all whom it lmay concern.'

Be it known that I, FRANK N. ROEHRICH, a citizen of the United States. residing at Jersey City, in the county of Hudson and State of New Jersey, have invented a new and useful Refrigerator-Thermostat, of which the following is a specification.

My invention relates to improvements in thermostats used either in automatic refrigerating systems or in automatic heating systems, but especially in the former. Such thermostats are divisable into three general classes. A

First, thermostats with their motor member made of two flat strips, such as brass and steel or rubber and steel. with their fiat surfaces secured together and fashioned in the form of a tongue or a helix, with one end pivoted and the other end free. so that with a rise of temperature the greater expansion of one material such as the brass, will forcel same material will force the free end of theV member in the opposite direction. into contact with a stationary low temperature con` tact. Such thermostats.however, have very little motor power and are adapted only for making and breaking el ctric contacts.

Second. .thermostats consisting of a chamber casing inclosing a high tension gas'or vapor. such as ammonia. and having as their motor member a movable wall forming one side of the chamber. Such a wall-may be in the form of' a diaphragm. clamped at its In one case, an increase of temperature and presure moves the center of the'dlaphragm outward.in opposition to a strong spring.,

and a decrease of temperature and pressure permits the spring to move the center of the diaphragm inward. In the other case, the free end of -the tube similarly overcomes or vields to a spring. llhile the pressure of the gas or vapor in such a thermostat. at any given temperature. is high. yet the change of pressure. occurring with a few degrees rise `or fall of temperature. is relativelyr .slight and the consequent net action upon or yielding to the spring is trifling. Such thermostats, also, are of slight power. The

advantages of both these two classes of thermostats is that the to-and-fro movements of their motor members are very considerable, being as much, if desired, as an eighth of an inch, or more, within a few degrees change of temperature.

Third.- thermostats that depend on the longltudlnal expansion and contraction of some solid, such as copper or hard rubber,

fas the motor member, to operate the short end or ends of one or of'a series of pivoted levers. Here the advantage is that the power exerted by the motor member is very great. But the disadvantages are that, for a slight change of temperature, the to-andfro movements of the lmotor member are very slight; and, unless the parts are made very heavy; there is a yielding of the material which greatly reduces the movement-s that are theoretically obtainable.

The main purpose of my invention is to construct a thermostat that will have a strength comparable with that of the third class, that will have a range of movements comparable with that of the first and second classes, that will avoid the disadvantages of all three classes, and that will be especially adapted for use in connection with refrigerating machines.

My invention further relates to improvements in apparatus wherein variations of Huid presure result in movements of a diaf phragm, forming part-of the casing wall contamlng the fluid. so as to, move mechanism adjacent lto the diaphragm. Insuch acon-- struction my purpose is to so connect a diaphragm with a casing wall that the diaphragm, though very thin, will not break under the Stress of normal working fluid pressures. y v

.My invention further relates to improvements in means for adjusting the range of circular movement of the outer end of a lever that is acted upon, near its yinner or pivoted endl by motor mechanism, especially when the lever constitutes part of a thermostat. In such a4 construction my purpose is to make such adjustments easy, accurate and strong.

There are also certain detail improvements of construction as will appear.

The means employed for accomplishing these purposes are disclosedin the accomroo panying drawings and in the description relating thereto.

In the drawings, Figure l is a partial iront elevation and a partial vertical secn tion of one form of my invention. Fig. 2

a partial plany view and a partial horizontal section through the line 2-2 of the Fig. 3 is an enlarged de-` Fig. 7 isr a partial vertical section and a partial front elevation ot a modified form of my invention, through the line 7-7 of the 'Y next gure, as attached to the right side wall of a compartment, such as a refrigerator. Fig. S is a partial right end elevation and a partial vertical section through the line 8 8 of the preceding ligure. Fig. 9

is au enlarged detail view ot' a part of Fig. 7 t

First considering Figs. l to 6 inclusive: A pipe l, shown in broken vertical section, is externally thfreaded, top and bottom, and should be ot such lengthl as required Jfor the purposes of its use, as will be hereinafter explained. A cup nut 2 has its side lwalls internally threaded and through the opening in its end wall is adapted to be slid over the lower end of the pipe 1. A lower casing 3 has an internally threaded sectionv for screwing over the lower end of the pipe 1; it has, at the top above its internally threaded section, a recess containing a packing 4t and above the packing a packing ring 5; and it is externally threaded at its extreme top. After the nut 2 has been slid over the lower end of the pipe 1, the casing 3. containing the packing l and the ring 5, is screwed around the lower end of the pipe; and then the nut is screwed around the top of the casing so that the ring compresses the packing and makes a tight joint between the pipe and the casing. The casing 3 also has. below its internally threaded section, a iianged section. 'of an internal diameter very considerably7 greater than that ot the pipe 1, having a recess adapted to contain a gasket G and being internally threaded below the gasket. 1 j

A flexible relief diaphragm T, preferably of thin metal, rests against the under side ot' the gasket G and tends a little to bend upward and inward; Adjacent to the under side ot the diaphragm 7 is a disk member S, having its disk part practically coextensive with themovable part of the diaphragm and haring a stem extending downward and integral hub 17 to the right.

threaded at its lower end. A compressing member 9 has an externally threaded upper section, corresponding to the lower internally threaded part of the casing 3; it has a plain upper inner section, litting around and under the disk part of the member 8 but permitting the latter to be slightly reciprocated; and it has an internally threaded lower section. After the gasket 6 has been placed in its recess, after the diaphragm 7 has been placed against the gasket and after the member 8 has been placed with its disk part against the diaphragm, the member 9 is screwed into the casing 3 so as to compress the gasket and to make a tight joint between the casing and the diaphragm.

A sleeve 10 is externally threaded top and bottom and has a central nut section whereby it is screwed into the lower section of the member 9. A heavy helical compression spring 11 is adapted to surround the stem of the member 8 and to abut against yits disk part. A cap 12 has a vertical central opening large enough for the passage through it of the lower end ot' the stem ot the member 8, and it is internally threaded for screwing around the lower end of the sleeve 10. screwed on to the sleeve 10 so that the threaded extremity of the member 8 projects through, a stop nut 13 is screwed around this extremity until the spring 11 has been given a desired tension and then the nut 13 is held in place by a lock nut 14.

Finally the cap 12 is screwed up just enough to cause the member 8 to bear against the diaphragm 7 without forcing it inward. The nut 12 may be screwed up. as described, until the spring 11 has been compressed to such an extent that it will not yield to pres- 'i sure, on the upper side of the diaphragm 7, until such pressure exceeds say 200 pounds per square inch; but the diaphragm and spring should be so proportioned that. .at'ter some such pressure has been exceeded, they will yield suiiiciently to permit of suchv an expansion of the liquid above the diaphragm as will occur, in manner to `be described. up to the maximum atmospheric temperature,

which may be taken as degrees.

An intermediate casing 15 has an internally threaded lower section, into which the upper end of the pipe l is screwed; it has an externally threaded upper hub 1G; it has a. vertical cylindrical chamber extending from top to bottom; and it has an opening extending from this chamber through `an 1 As, the opening through the hub 1T proceeds to the right from the chamber ot' the vcasing 13. there is irst a threaded section. second a plain section of greater diameter. `third a packing section ot yet greater diameter and finally a threaded section ot greatest diameter. A

rod-like regulator 1S is externallythreaded than does its inner slope.

at its inner end so that it may be screwed into the innermost section of the hub 17 ;v

it has a central longitudinal passage 19 extending from it-s inner end for a distance nearly equal tothe length of the hub from the inner end of the latter as far as the outer end of the plain section; it has a transverse passage Q0, extending from the outer end of thev passage 19 to the outside of the regulator, so as to connect the passage 18 with the space in the plain section; and it terminates in a. wrench section at its outer end. After the space above the diaphragm 7 has been illed with liquid,as will be described, and afterthe regulator 18 has been screwed into the hub 17, a packing ring 21.is placed in the packing section of the hub; a lock nut `.2:2 'is screwed around a gland 'nut Q3; the nut '23 is screwed into the outermost threaded section of the hub, so as to compress the ring and tomake a tight joint between the hub and theregulator; and then the nut 2-2 is screwed up so as to hold in place the lnut 23. It is apparentthat. after loosening the nuts 22 and 23, the regulator 18 may be screwed farther in or farther out and that thereafter the nuts may again be tightened.

The hub 16 has near its top, around its contained chamber and above its threads, a section Q-.t of reduced diameter and, surmounting the section, an annular and slightlyv convex rim 25 of the shape best shown in Fig. 3. The outer slope of the rim 25 is longer and extends farther down Resting on the shoulder formed by the reduction of the. diameter of the hub 16, and around thesection 24, is a gasket :26 that .extends upward as far as the bottom of the outer slope of the rim 25. A motor diaphragm 27, preferably7 of very thin metal, rests on the rim Q5 andthe gasket 26. r

An upper casing '28 has 'a horizontal partition 29, with a cylindrical opening extending centrally and vertically through \the partit-ion: ithas below the partition a vertical cylindrical reciprocating chamber of substantially the same diameter as the chamber in the casing 15; it has at its extreme lower end an internally threaded section for screwing 'on to the hub 16; it has above this threaded ction a recess section so as to surround andbear upon the outer edge of the diaphragm 2T and the gasket Q6: and. between the recess section and the reciprocating chamber. it has a concave formation. as best shown in exaggerated form in Fig. 3. so as to permit. the diaphragm to swell out a slight distance and then to bear evenly upon the casing. Resting flat upon the diaphragm '2'. and adapted for reciprocation in the reciprocating chamber of the casingQS. is a foot 30, having on top a c vlindrical cavity. When the casing 28, containing the foot 30,l is screwed down upon the hub 16, it compresses an annular section of the diaphragm 27 both upon the gasket 26 and also upon the lower edge of the outer slope of the rim 25; and-it compresses the gasket so as to make a tight joint between the hub and the diaphragm.

The parts are so constructed and formed that when the diaphragm 27 occupies a central position, as shown, it has its periphery resting flat upon the gasket 26; it has an annular section inclined upward and resting on the outer slope of the rim 25; and it has its central part extending flatly across the space within the top of the rim; But when the diaphragm 2T is forced inward, an annular section of its central part tends to resten the inner slope of the rim And when the diaphragm 27 is forced outward, the central, part swells outward so that, as viewed in vertical section, this central part tends to make smooth curves with the annular section resting on the' outer slope of vsection outside of another annular section upon which is the greatest stress upon an inward movement of the diaphragm.

The compressing of the diaphragm 27, upon the lower edor of the outer slope of the rim 25. leaves an annular section, around the upper' part 'of the slope, open to the action of the liquid in the casing 15, on outward movements of the dlaphragm. The concavity of the casing 28 above the diaphragm is such that. when the foot is moved outward say a thirty-second of an inch, the diaphragm may bear evenly on the foot and casing and may be backed and supported thereby at all points just as etfectually as if resting against a solid wall. Assuming that the outwardv movement of the foot 30 is properly limited, as will be shown. this con-` struction of the diaphragm and of its adjacent parts eiectually protects the diaphragm against injury by fluid pressure on its under side. however great such pressure may be. The construction of the rim Q1 above referred to, on an inward movement of the diaphragm QT, shifts the stress from an outer annular section of the diaphragm to an inner annular section. So that the total effect is to make the diaphragm 2 7, if of suitable material, to be very durable.

It also is to be noted that the diameter of the foot 30 is nearly as great as the diameter of the movable part of the diaphragm 2T. By this construction. it being assumed that the diaphragm '2T is of suchmaterial and thinness as to exert a minimum of resistance, the diaphragm. as an instrument for moving the foot 30, approximates a piston in eliiciency. It would be otherwise with a diaphragm of relatively small diameter. vThis construction would be of even greater importance if the diaphragm 30 were to be acted upon by a gas or vapor, instead of, as preferred in the present structure as an entirety, by a liquid.

The upper part of the casing 28 has above its partition 29 a vertical cylindrical recip rocating chamber; it has above this chamber at its top a section that is threaded both internally and externally; and, for a distance extending from its top nearly to its part screwing around the hub 16, its exterior diameter is lessened suiiciently so as to leave a hexagonal shoulder at its lower end. A stop ring 3l and a lock ring 32 are adapted to reciprocate slightly in the reciprocating chamber of the casing 2.8 above its partition 29. A reciprocating rod 33 has, at its lower end, a section of reduced diameter, adapted for reciprocation through the opening in the partition 29 and to it into the cavity of the foot 30; it has, above its section of reduced diameter, an intermediate threaded section for screwing into the rings 31 and 32; and it has, above its Vthreaded section and for most of its length, a plain section.. After the rod 33 has been screwed into the rings 31 and 32, and after the ring 32 has been screwed up so as to hold the ring 3l in proper longitudinal position, the rod is inserted into the casing 27 so that its lower end passes through the partition 29 and occupies the cavity in the foot 30 and so that the ring 31 rests on the partition. An externally threaded stop sleeve 34 is adapted for screwing into the top of the casing 27 so as to loosely sur-v round the rod 33; and it has a nut section at its top. A lock nut 35 is adapted for screwing around the sleeve 34 nearly up to the nut section. After the nut 35 has been screwed up on the sleeve 34, the sleeve is screwed into the casing 27 until its lower end is a short distance above the ring 32 and then the nut is'screwed down so as to hold the sleeve in its longitudinal position. Surmounting the top of the rod 33 is a knife edge bearing 36, having a cavity on its under side tting over the rod.

The parts are so constructed and adjusted that, when the rod 33 is in its lowest position, it bears upon the foot 30 so as to very slightly depress the diaphragm 27 but it is prevented from further thrusting upon the diaphragm by the contact of the ring 3l with the partition 29; and the foot and rod are free to move upward a thirty-second of an inch, but no farther, by the contact of the ring 32 with the sleeve 34. Obviously the parts could be so adjusted as to provide for some other range of movement of the reciprocating parts. But a range of a thirty-second of an inch is selected because that is sufiicient and yet is not so great as to strain the diaphragm 27. It is intended, moreover, that whatever range of movement is once or screwing the bracket to any convenient vertical surface. of the bracket 37 and its lower cross arm 1s Between the vertical part a section with a vertical cylindrical openi ing whereby the bracket ts snugly over the top of the casing 23 and firmly rests on its shoulder. A nut 33 screws over the top of the casing 28 and down upon the bracket 37 so as to hold them tightly together. By attaching the bracket 37, through its cross arms` to any convenient vertical surface,

all the fixed parts below and above the casing 23 are held rigid. ln the vertical part` lof the bracket 3i' is a longitudinal slot 39,

extending from left to right. In the top ot' t-he bracket 3T is a longitudinal slot 40, extending into the slot 39, of a width., from. back to front, a trifle over the diameter of a bolt 4l,.and of a width, from left to right, nearly as much again as that diameter.

At the top of the slot 39, and extending` across the lower end of the slot 40,- is thel upper flat side of a knife edge pivot42, having in its upper part a threaded. vertical cavity and having a knife edge at its lower end. A washer 43 `rests on top vor the bracket 37 around the slot 40. On passing` the bolt 41 through the washer 43 vand the slot 40, and screwing it into the cavity of the pivot 42, the pivot is firmly secured to the bracket 37. It is furthermore evident that, on slightly unscrewing the bolt 41, the

position of thebolt, the washer 43 and the pivot 42 may be shifted back and forth, as

desired, as far as the left to right width of the slot 40 permits.

A lever 14, shownin broken front elevation, has on top, at its extreme left or inner end., a transverse angular groove adapted to hold the knife edge of the pivot 42; it has, a short distance from its inner end, on its under side a transverse rectangular groove: and it has.ab. ve this latter groove, a circular opening extending from back to front. A yoke 45 rests-against the under side of the iev-nf 44 in its rectangular groove; it has arms. extending up against the lever in back and in front; it has, on its under side, a transverse angular groove adapted to seat over the knife edge of the bearing 36; and it has. in its arms, slots registering with the circular opening through the lever but of greater dimensions from lett to right than is the diameter of the opening. A. small belt 46 passes through the slots of the voke 45 and the opening of the lever 44. The le`ver44, with the parts 45- and 46 in position upon it, is

inserted, atiits inner end, into the slot 40 so that its upper groove bears .against the knife edge of the pivot 42 and so that the groove of the voke 45 bears upon the knife edge of the bearing 36.

The distance between the knife edges of the pivot 42 and the bearing 36 determines the distance that the outer end of the lever 44 is moved up or down when the diaphragm 27 is moved up or down. That is to say, if this former distance ,is one inch and if the effective length of the lever 44,

` as measured from its top groove, is eight right dimensions of the slot 40.

inches, then, on a movement of the diaphragm of one thirtyl'second of an inch, the outer end of the lever will move a. quarter of an inch. But, furthermore, the left to right dimensions of the slot in the yoke 45 and of the rectangular groove in the lever 44 are made to correspond to the left to Consequently, when the bolt 41, the washer 43 and the pivot 42 are moved as far to the right as the slot 40 permits, the bolt 46 may be moved in the 4slot of the voke 45v and the yoke may be move-d in the rectangular groove of the lever 44 an equal distance to the left; and, upon a tightening up of the parts after such movements; a new adjustlnent of the lever is accomplished, for itis evident that, upon such adjustment, the dis` tance between the knife edges of the pivot 42 and the bearing 36 is correspondingly decreased and the range of movement of the outer end of the lever 44 is correspondingly increased. It is also evident that, between the extreme distance apart between the knife edges of the pivot 42 and the bearing 86, there are intermediate distances that can be established. Consequently, if, on movements of the diaphragm 27, the outer end of the lever 44 has too great or too little movement, the proper decrease or increase of the levermovements can be had by a readjustment of the parts specified.

A bracket 47, attachable to some convenient surface in a manner not shown. has in its upper arm a vertical cylindrical opening, through which reciprocates the upper end of a rod forming part of a link member 48. The member 48 has a disk at the lower end of its rod; it is pivoted, below its force downward the lever 44`and the intery' mediate parts above thediaphragm 27 and also the member 48 and any mechanism connected therewith. The spring 50 is much weaker than the spring 11 and must never 28. 27. 15. 18. 13. 7 and 9. any liquid is suitable that has a high coeiicient of expansion and that is serviceable in other particulars. For use in a refrigerator thermostat, I prefer alcohol, on account of its very considerable expansiveness, its cheapness, its safety in handling and its non-action on all metals that may be used to form the containing chamber. Benzene has many of the advantages of alcohol; but it is not so safe in handling. For temperatures below 54 degrees, ethyl chlorid is very desirable on account of its high expansiveness; but it is also somewhat expensive; and, just above that temperature, lit vaporizes and in a va-porous condition. as would any gas or vapor, it would nullify some important advantages of my construction. lith all three liquids, the diaphragms 7 and 27 may be of vanadium steel or of phosphor bronze: the gaskets 6 and 26 may be of lead: and the other containing parts may be of brass or iron or steel. Mercury. in so far as its expansiveness is concerned. is the ideal motor r heating system for the maintenance of room temperatures. But for a. thermostat to l1m1t the heating of an ammonia still, in an automatic absorption refrigerating where the temperature limit is say 300 degrees, I prefer mercury to the exclusion of all other liquids, the containing chamber, in such case. being quite small. lith any liquid, the hub 17 is turned uppermost, the motor liquid is poured in to fill theentire chamber, the regulator 18 is screwed in and the adjacent parts are secured in place as has been described. J

Assuming that the thermostat is to be used in connection with a refrigerator, and for the maintenance of a temperature range say of four degrees. the parts of the containing chamber. especially including the parts 1, 2, 3, 8 and 9 and also 15 apart from the hub .16. but'excluding the parts 16, 27 and 28, which should remain constant, are so proportioned that, with the particular motor liquid to be used, preferably alcohol, on a four point rise of temperature. the increase in volume of the motor liquid will distend upward the diaphragm 27 one thirty-secondth of an inch at the center, and, on a subsequent four point back drop of temperature, the decrease in volume of the liquid will permit thev spring 5t), and the intermediate parts, to move the'diaphragm through the same distance back to its original posltion. The

machine,

thermostat, having been filled so nearly full that the regulator 18 is substantially in its extreme outer position, is mounted and suitably connected in the refrigerator; and, by apparatus assumed to be in operation, the refrigerator is cooled down say to 37 degrees. Then, or previously, the regulator 18 is gradually screwed in until,'at that temperature, the diaphragm 27 is in its highest position, as evidenced by the extreme elevated position of the outer end of the lever 44. The nuts 23 and 22 are adjusted into securing positions. Then, as the refrigeration progresses and the temperature in the refrigerator gradually drops to 33 degrees, with a decrease in volume of the liquid, the spring 50 presses on the member 48 so as to depress the parts 44, 4G, 45, 38, 33, 32,` 31 and 30 until the diaphragm 27 is forced into its lowest position, but no farther, owing to the ring 39 coming into Contact with the partition 29. lt is assumed that, in consequence of this depression of the member 48, unshown connected mechanism now temporarily terminates the refrigeration. Consequently, as the temperature in the refrigerator begins to rise, the volume of the motor liquid begins to increase and its pressure forces upward the diaphragm 27 and the intermediate parts so as to compress the spring 50 until the ring 32 comes into contact with the sleeve 34 and the diaphragm lies dead against the foot 30 and the casing 28. The member 48 now operates to again start the process of refrigeration and the ordinary cycle OfoperatiOn is complete. As before explained, the range of movement of the outer end of the lever 44, and hence of the member 48, may be altered by adjustments of the pivot 42 and the yoke 45 and pin 46. New suppose, however, that the apparatus operating to cool the refrigerator 1s shut down, so that the temperature around the thermostat rises above 37 degrees and becomesfthat of the atmosphere. ln consequence of the regulator 18 having been screwed inward from. its initial position, it happens that the motor liquid expands with such tremendous force that it would burst its containing casing, were it notl for the relief diaphragm 7 and the other parts operative inV connection therewith, which other parts constitute a relief mechanism. As it is, this super-increase in volume simply acts through the diaphragm 7 on the member 8 so as to compress the spring 11. 0n a resumption of refrigeration, and a cooling down of the temperature to 37 degrees, the spring 11 forces the member 8 and the diaphragm 7 back into place, where they remain inactive so long as the process of refrigeration continues.

ln case, owing to the proportions of the parts, the regulator 18 cannot be screwed in far enough from its initial position to force the diaphragm 27 into its highest position at 37 degrees, the desired result can be attained by screwing the regulator back to its initial position, by loosening the nut 2, by screwing the casing 3 farther upbe maintained, the manner of proportioning the parts, and the method of adjustment, are deemed to be apparent from the foregoing explanation.

lVhere the thermostat is intended to operate at temperatures higher than that at which the motor liquid is poured in, there must be a reversal of the method of adjustingr the volume of the liquid. That is to say, if the regulator 18 alone is to be used for adjusting the volume of the liquid at the operating temperature of the thermostat, the initial position of the regun lator, after pouring in the liquid, should be as far inward as possible; then, as the volume of the liquid increases, the regu-- lator should be screwed outward until it is in its proper outward position, with the diaphragm 27 in its extreme high position, at the desired maximum temperature limit. But if the regulator 18 is to be supple- Inented as above indicated,for a preliminary rough adjustment of the volume of the liquid, the initial position of the casing 3 should be high up on the pipe 1; then, as the volume of the liquid increases, loosen the nut 2, screw the casing farther down on Ythe pipe and again tightenthe nut. Finally make the fine adjustment with the regulator 18.

The parts 28, 26, 27, 16, 15, 17,V 18, 21, 22, 23, 1, 2, 5, 4, 3, (i, 9 and 7, when the latter is maintained in its upper position by its adjacent reliefy mechanism, constitute a motor member that is similar in operation to a copper or hard rubber rod or tube forming the motor member of many types of thermostats, as illustrated in the patents to Ruud, 443,797, Dec. 30, 1890, and 460,513, Sept. 29, 1891. But in my construction, to obtain a given longitudinal movement at the end of the motor membeig l am not obliged to make it of any particular length, which for my purposes would have to be very considerable, but can rely on a suliiooY ciently great diameter of the pipe 1 and other adjacent parts. My relief :mechanism, moreover, is of value in connection with a thermostat using any solid substance as a motor member, it being apparent, assuming that the movement of the head of the motor member is limited, that, instead of an initial adjustment of the spring 11 as I have described, the spring might be gradually adjusted after refrigeration had begun in much the same manner as the regulator 18 is adjusted. Furthermore, with a motor lnember consist-ing entirely of a rod or tube, expanding longitudinally, such a rod or tube is liable to bend under pressure and thus to render the therlnostat, in part or in whole. inactive and ineifectual. Such a diiculty is quite avoided in my construction. On the other hand, if my thermostat is operated at temperatures above that of the atmosphere, as in terminating the heating of an ammonia still in an automatic absorption refrigerating s vstem, the diaphragm 27 and the parts below it have no greater function than other immovable parts of the chamber wall and can well be replaced by a mere wall. Curiously enough, however, if mv thermostat is used to control room temperatures, the relief mechanism is of prime importance. For suppose the parts are so constructed and adjusted as to maintain in a room, through proper heating apparatus, a temperature range say of to 72 degrees. Then, in summer time, as the atmospheric temperature rises above 72 degrees, there is preciselvv the same excess volume and pressure on the walls of the chamber casing as with the refrigerator.

The ordinary means for connecting a dlaphragm with a casing wall are illustrated in the case of the diaphragm 7 and the diaphragm 7a, to be described. Such means are sutiicient where the diaphragm is not required to be sensitive to slight changes of fluid pressure and where, consequently, it may be relatively thick. But with a very thin diaphragm, it is apparent that the shearing strain upon the diaphragm, as it is moved both inward and outward, along the same circular line, is certain eventually to cause a breakage that is impossible in case of the diaphragm 27. And by the formation of the casing 28 and the foot 30, and by limiting the movements of the latter, IY dispense with the need of any diaphragm reinforcement, such as is illustrated in the ,patents to Knowles, 18,048, Aug. 25, 1857,

and to Thomson, 832,708, Oct. 9, 1906. It further is to be noted, in the construction of the diaphragm 27 and its adjacent parts, that while the foot 30 is on the outside of the diaphragm. my means for connecting a. diaphragm with a casingwall are equally available in those valve constructions Where a member, corresponding to the foot 30, is adjacent to the inside of`a diaphragm andoperates, as the diaphragm tends to move outward, to tend to close a 4valve seat, Such a valve construction is illustrated in the patent to Gold, 508,133, Nov. 7, 1893.

`In the case of the means for pivoting and i actuating the lever 44'it will be noted that the means for adjusting the distance apart of the pivot 42 and' the bearing 36, do not depend upon the knife edge and groove construction shown and described; nor do said means depend on the peculiar construction of my motor member. For these same means are available with the ordinary pin pivots and bearings and with a motor member wholl)v of solid material, as illustratedv in the patents to Ruud, abovemreferred to.

Finally considering Figs. 7 to 9 inclusive: Here the parts that are so similar to parts'already described, as to need no further description, are indicated by the numerals an. 4a, 5a, 6a, 7a, sa, 9a, 10a, 11a, 12a,

long and narrow vertical opening that isv .adapted to be occupied and sealed by4 a section 52, having around its external edges a hollow rectangular plate 53. Through holes in the edges ofthe plate 53, screws 54 secure the plate to the wall 51. A high,

cept that on top it has a threaded opening, enlarging into a stuflng box recess. A pipe 56, having a. descending elbow at its inner end, has the threaded lower end of this elbow screwed into the opening of the .narrow tank 55 is inclosed on all'sidesi, ex-

tank 55 and is threaded for most of its horizental length. A packing ring 57, .around the'pipe 56 in the recess of the tank 55, is pressed down by a gland nut 58 so as to make a tight joint between the pipe and the tank. A large ring 59 clamps around the tank 55 near its lower end and has integral with itself a rod 60, extending horizontally, parallel with the horizontal part of the pipe 56 and threaded at its end. A flanged inner upper ring 61 screws on to the horizontal part of the pipe 5,6 anda flanged inner lower ring 62 screws on to the rod 60. The pipe 56 and the rod 60 are so spaced apart that, carrying the rings 61 and `62, they pass through openings-in the section 52 and are clamped in place by a flanged outer upper ring 63, screwing around the pipe, and by a flanged outer lower' ring 64, screwing around the rod. The parts are so proportioned that the section 52, carrying the parts 53, 55, 56, 57, 58, 59. 60, 61, 62, 63 and 64:.'

can be inserted into the opening in the wall 51, so as to maintain the parts in the position shown in Fig. 7 and also to occupy and seal the opening i An intermediate casing 65 has its parts at the top and rightjlike those of the casing 15 and it has a chamber extending from top to 6a above the diaphragm 7 a, but there is also a gasket 66 below the diaphragm against which the member 9a` is screwed. Here, also, the outside diameter of the casing 65 is sutiiciently great to render unnecessary a flange on the casing 3a. Furthermore, at the right oit the casing 15, in axial alinement with the opening containing the regulator' 18, is another opening 6T, threaded near its outer end and enlarging into a gasket recess 68.

After the pipe 5G has been passed through 'the section 52 and has been clamped in place, a counter bored nut G9 is screwed over the pipe, with its recess outward. The pipe 56 has also near its extreme end a plain section of reduced diameter. A gasket 7 0 occupies the recess (3S and a ring 71 just enters the recess so as to cover the gasket. The casing G5 and the pipe 56 are then screwed together so that the gasket '(0 and the ring Tl surround the plain section ot the pipe. And the nut G9 is screwed down over the ring 7l, with its recess over the ring, until the gasket TO is so compressed as to make a tieht joint. 'These means for connecting the casing G5 and the pipe 56 are set forth and claimed in my application Ser. No. 717,142, filed Aug. 2G, 1912, entitled Ammonia pipe union.

A bracketJ 72, similar to the bracket 3'4", but having its cross arms to the left of its vertical part, is secured by screws 73 to the outside of the Wall 51. A half collar 74C is secured b bolts T5 to the bracket 72 so as to firmly hold the upper casing 28 )ust above its shoulder, and is pressed uponby the nut 3Se As compared With the former construction, especially in connection with refrigerators, the modified construction has certain important advantages. By placing scarcely anything more than the tank 55 Within the refrigerator, the inside space is economized, all adjustable parts are more easily accessiblc. and, if the mechanism to be connected with the member 4S is outside, provision docs not have to be made ttor the passage ot the operating lever through the Wall of the refrigerator. The parts containing the motor liquid are so proportioned that the liquid in the casing (i5 docs not affect the action of the liquid in the tank 51. And in other respects the modilied thermostat operates as does the former construction.

ll'hat l have invented and what desire to have protected b v Letters Patent is expressed in claims as follows:

l claim:

l. ln combination a temperature controlled motor member, movement multiplying mechanism in operativo relation with said member, n ans operating on a predetermined rise of temperature about said member to permit it to move said mechanism a predetermined distance and on a sub- Lirama sequent fall of such temperature to cause said mechanism to follow said member back to its initial position, means operating in case of an excess of temperature about said member above such predetermined rise to permit of a temporary expansion of said member in a part thereof other than in the part operative upon said mechanism, and means for increasing or decreasing the range oit maximum movement of said mechanism.

2. ln combination a chamber casing, a diaphragm inclosing said casing, a liquid occupying the space Within said casing and diaphragm, movement multiplying mechanism in operative relation With said diaphragm, means operating on a predetermined rise of temperature about said liquid to permit said diaphragm' to more said mechanism a predetermined distance and on a subsequent tall of such temperature to cause said mechanism to follow said diaphragm back to its initial position, means operating in case of an excess oi temperature about said liquid above such predetermined rise to permit of a temporaivT eXpansion of a part et' said casing, and means for increasing or decreasing the range of maximum movement of said mechanism.

3. ln combination a chamber casing having two diaphragm openings, a motor diaphragm closing one of said openings, a relief diaphragm closing the other of said openings, a liquid occupying the space within said casing and diaphragme, movement multiplying mechanism in operative relation with said motor diaphragm, means operating on a predetermined rise oi? temperature about said liquid to permit said motor diaphragm to move said mechanism a predetermined distance and on a subsequent tall of such temperature to cause said mechanism to 'folion' said diaphragm back to its initial position, relief mechanism preventing an outward movement of said reliern diaphragm during such temperature changes but temporarily permitting such a movement in case oi an excess ot temperature about said liquid above such predetermined risc, and means for increasing or decreasing the range ot maximum increment ot said multiplying mechanism. i

4.-. ln combination a chamber casing` a diaphragm inclosing said casing, a liquid occupi-'ing the space within said easing and diaphragm, means for adjusting a part ot the casing wall containing said iiquid so as to bel farther in or farther out, movement multiplying mechanism in operative relation with said diaphragm. means operating on a predetermined rise of temperature about said yliquid to permit. said diaphragm to more said mechanism a predetermined distance and on a subsequent Jfall of such temperature to cause said mechanism to follow said diaphragm back to its initial position, and

means for increasing or decreasing the range of maximum movement of said mechanism.

5. In combination a chamber casing, a diaphragm inclosing said casing, a liquid occupying the space within. saidV casing and diaphragm, means for adjusting a part of the casing wall containing said liquid so as to be farther in or farther out. movement multiplying mechanism in operative relation with said diaphragm. lneans operating on a predetermined rise of temperature about said liquid to permit said diaphragm to move said mechanism a predetermined distance and on a subsequent fall of such temperature to cause said mechanism to follow said diaphragm back to its initial position, means operating in case of an excess of temperature about said liquid above such predetermined rise to permit of a temporary expansion of a part of said casing, and means for increasing or decreasing the range of maximum move- 4ment of said mechanism.

ing said liquid so as to be farther in o1'- farther out. movement multiplying mechanism in operative relation with said motor diaphragm. means operating on a predetermined rise of temperature about said liquid to permit said motor diaphragm to move said mechanism a predetermined distance and on a subsequent fall of such temperature to cause said mechanism to follow said diaphragm back to its initial position, relief mechanism preventing an outward movement of said relief diaphragm during such temperature changes but temporarily permitting such a movement in case of an excess of temperature about said liquidv above such predetermined rise, and means for increasing or decreasing the range of maximum movement of said multiplying mechanism.

T. In combination a chamber casing having a diaphragm opening and a threaded regulator opening, a diaphragm closing said diaphragm opening. a liquid occupying the space within said casing and diaphragm, a regulator screwed into said regulator opening into contact with said liquid and adapted to be screwed farther in or farther out` means for making a tight joint between said regulator and said casing, movement multiplving mechanism in operative relation With said diaphragm, means operating on a predetermined rise of temperature about said liquid to permit said diaphragm to move said mechanism a predetermined distance and on a subsequent fall of such temperature to cause said mechanism to follow said diaphragm back to its initial position, and

means` for increasing or decreasing the range `0f maximum movement of said mechanism.

. diaphragm opening, a. liquid occupying the space within said casing and diaphragm, a-

regulator screwed into said regulator opening into contact with said liquid and adapted to be screwed farther in or farther out, means for making a tight joint between said regulator and said casing, movement multiplying mechanism in operative relation with said diaphragm, means operating on a predetermined rise of temperature about said liquid to permit said diaphragm to move said mechanism a predetermined distance and on a subsequent fall of such temperature to cause said mechanism4 to follow said diaphragm back to its initial position, means operating in case of an excess of temperature about said liquid above such predetermined rise to permit of a temporary expansion of a part of said casing, and means for increasing or decreasing the range of maximum movement of said mechanism.

9. In combination a main chamber casing having a motor diaphragm opening, a

threaded regulator opening and a threaded section with an opening through it, a motor diaphragm closing said motor diaphragm opening, a threaded casing screwed on to said threaded section, having through 1t a relief diaphragm opening and adapted to be screwed farther in or farther out, means for making a tight jointl between said threaded casing and said main casing, a

liquid occupying the space within said casings and diaphragms, a regulator screwed into said regulator opening into contact with said liquid and adapted to be screwed farther inI or farther out, means for makmga tight joint between said regulator and said main casing, movement multiplying mechanism in operative relation with said motor diaphragm, means operatin on a predetermined rise of temperature a out said liquid to permit said motor diaphragm to move said mechanism a. predetermined distance and on a subsequent fall of such temperature to cause said mechanism to follow said motor diaphragm back to its initial position, relief mechanism preventing an outward movement of said relief diaphragm during such temperature changes but temporarily permitting such a movement in case of an excess of temperature about said liquld above such predetermined rise, and means for 1ncreasing or decreasing the range of max unum movement of said multiplying mechanism.

10. In combination a bracket, a plvot attachable to said bracket and adapted to be shifted into various forward and back positions in relation thereto, means for detachably clamping said pivot to said bracket in any such position, a leverlpivoted on said pivot, a motor having a bearing, a yoke bearing on said bearing, attachable to said lever and adapted to be shifted as far back on the lever as said pivot is shifted forward on said bracket and as far forward on the lever as the pivot is shifted back on the bracket. and means for detachably securing said yoke to said lever in any such position.

11'. In combination a bracket, a pivot attachable to said bracket, terminating in a knife edge and adapted to be shifted into various forward and back positions `in relation thereto, means for detachably clamping said pivot to said bracket in any such position, a lever having a groove registering with said edge, a motor having a knife edge bearing, a yoke having a groove registering with the edge of said bearing, attachable to said lever and adapted tobe shifted as far back on the lever as said pivot is shifted forward on said bracket and as far forward on the lever as the pivot is shifted back on the bracket, and means for detachably securing said yoke to said lever in any such position.

1:2. ln combination a bracket with a vertical slot extending from an upper to van under surface thereof, a pivot adapted to be slid forward and back along said under surface, clamping means passing through said slot but occupying only a part of the space therein as measured forward and back and detachablyl clamping said pivot to said under surface in any such forward or back position, a lever pivoted on said pivot, a motor having a bearing, a yoke bearing on said bearing, attachable to said lever and adapted to be shifted as far back on the lever as said pivot is shifted forward on said under surface and as far forward on the lever as the pivot is shifted back on said under surface, and means for detachably securing said yoke to said lever in any such position.

13. ln .combination a bracket with a vertical slot extending from an upper to an under surface thereof, a pivot adapted to be slid forward and back along 4said under surface and terminating in a knife edge at its lower end, clamping means passing through said slot but occupying only a part of the space therein as measured forward and back and detachably clamping said pivot to said undersurface in any such forward or back position. a lever having a groove registering with said edge, a motor having a knife edge bearing with its edge uppermost, a. yoke having a groove on its under side registering with the edge of said bearing, attachable to said lever and adapted to be shifted as far back on the lever as said pivot is shifted forward on said under surface and as far forward on the lever as the pivot is shifted back on said under surface/and means for detachably securing said yoke to said lever in any such position.

14. ln combination a bracket, a pivot attachable to said bracket and adapted to be shifted into various forward and back posi tions in relation thereto, means for detachably clamping said pivot to said bracket in any such position, a lever having through it a transverse opening and pivoted on said pivot, a motor having a bearlng, a yoke bearing on said bearing and having arms 1nclosing said lever and with slots in the arms registering with said opening, and clamping means passing through said slots and opening but occupying only a part of the space therein as measured forward and back and detachably clamping said arms and lever, the forward and back dimensions of said slots and kopening being such that said yoke may be shifted as far back on said lever as said pivot is shifted forward on said bracket and as far forward on the lever as the pivot. is

shifted back on the bracket.

15. In combination a bracket, a pivot attachable to said bracket and adapted to be shifted into various forward and back positions in relation thereto, means for detachably clamping said pivot to said bracket in any such position, a lever having through .it a transverse opening, having a transverse slot on its under side and pivoted on its pivot, a motor having a knifeedge bearing with its edge uppermost, a yoke positioned in said slot, having a groove on its under side registering with said edge and having arms inclosing said lever and with slots in the arms registering with said opening. and clamping means passing through said arm slots and opening but occupying only a part of the spa/ce therein as measured forward and back and detachably clamping said arms and lever, the forwardand back dimensions of all said slots and of said opening being such that said yoke may be shifted as far back on said lever as said pivot is shifted forward on said bracket and as far forward on the lever as the pivot is shifted back on the bracket.

16. In combinationV a bracket with avertical slot extending from'an upper to an under surface thereof, a pivot adapted to be slid forward and back along said under surface and terminating in a knife edge at its lower end. clamping means passing throughY said slot but occupying only a part of the space therein as measured forward and back and detachably clamping said pivot to said under surface in any such forward or back position, a lever having through it a transverse opening, having a vtransverse slot on its under side and having a groove register.- ing with said edge, a motor having a knife edge bearing with its edge uppermost, a yoke positioned in said slot, having a groove on its under side registering with the edge of said bearing and having arms inclosing said lever and with slots in the Larms registering with said opening, and 'clamping means passing through said arm slots and opening but occupying only a part of the space therein and detachably clamping said arms and lever, the forward and back dimensions of said lever and arm slots and of said opening being such that saidr yoke may be shifted as far back on the lever as said pivot is shifted forward on said bracket and as far forward on the leveras the pivot is shifted back on the bracket.

17. In combination a pivoted lever niember adapted to be turned inward and outward, an intermediate member bearing on said member near its pivot andonbeing moved outward turning said member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with increases and decreases of temperature and upon a predetermined expansion moving said intermediate member to lts outward l1m1t, and means upon a subsequent contractlon of said motor member moving said lever member and intermediate member to the inward limit said limiting means.

18. In combination a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing on said member near its pivot and on being moved outward turning said member outward, limiting means limitin the inward and outward movements of sai 'intermediate member, a motor member expanding and contracting with increases and decreases of temperature and upon a predetermined expermitted by pansion moving said intermediate member' to its outward limit, means upon a subsequent contraction of said .motor member moving said lever member and intermediate member to the,inward limit permitted b v said limiting means` and means for increasing or decreasing the range of maximum movement of said lever member.

19. In combination a pivoted lever`member adapted to be turned inward and outward, an intermediate member bearing on said member near its pivot and on being moved outward turning vsaid member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor'member expanding and contracting with increases and decreases of temperature and upon a. predeterminedexpansion moving said intermediate member to' its outward limit, and means upon a subsequent contraction of said motor member moving said lever member and intermediate member to the inward limit permitted by said limiting means, said elements being so operative at sub-atmospheric temperatures.

' 20. In combination a pivoted lever mem- -and means for increasing ordecreasing the range of maximum movement of said lever member. l

21. In combination a pivoted lever member adapted to be turned. inward and outward, an intermediate member bearing on said member near 1ts pivot and on being -lnoved outward turning said member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with\ increases and decreases of temperature and upon a predetermined expansion moving said intermediate member to its outward limit, means upon a subsequent contraction ofsaid motor member moving said lever mem and intermediate member to the inward mit permitted by said limitingmeans, and relief mechanism permitting an expansion of said motor member -in a direction other than toward said intermediate member upon the limiting by vsaid limiting means of an outward movement of the intermediate member.

In combination a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing onA said member near its pivot and on being moved outward turning said member outward, limiting means limiting the inward and outward movements of said intermediber to its outward limit, means upon a subsequent contraction of said motorl member moving said lever member and lntermediate member to the inward limit permitted by12er said limiting means, relief mechanism permitting an expansion of said motor member in a direction other than toward said intermediate member upon the limiting by said ber adapted to be turned mward and outward, an intermediate member bearing on said member near its pivot and` on being moved'outward turning said member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with increases and decreases of temperature and upon a predetermined expansion moving said intermediate member to its outward limit, means upon a subsequent contraction of said motor member moving said lever member and intermediate member to the inward limit permitted by said limiting means, and means for adjusting the expansion and contraction of said motor member so as to correspondwith predetermined temperature changes.

24. ln combination a pivoted lever member adapted to be turned inward and outward. an intermediate member bearing on said member near its pivot and on being moved outward'turning said member outward. limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with increases and decreases of4 temperature and upon a predetermined eX- pansion moving said intermediate member to its outward limit. means upon a subsequent contraction of said motor member moving said lever member and intermediate member to the inward limit permitted by said limiting means, means for adjusting the expansion and contraction of said motor member so as to correspond with predetermined temperature changes, and means for increasing or decreasing the range of maximum movement of said lever member.

25. ln combination a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing on said member near its pivot and on being moved outward turning said member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with increases and decreases of temperature and upon a predetermined eX- pansion moving said intermediate member to its outward limit` means upon a subsequent contraction of said motor member moving said lever member and intermediate member to the inward limit permitted by said limiting means, relief mechanism permitting an expansion of said motor member in a direction other than toward said intermediate member upon tbe limiting by said said member near its pivot and on being moved outward. turning said member outward, limiting means limiting the inward and outward movements of said intermediate member, a motor member expanding and contracting with increases and decreases of temperature and upon a predetermined expansion moving said intermediate member to its outward limit, means upon aA subsequent contraction o said motor member moving said level' member and intermediate member to the inward limit permitted by said limiting means, relief mechanism permitting an expansion of said motor-member in a direction other than toward said intermediate member upon the limiting b v said limiting means of an outward movement of the intermediate member, means for adjusting the expansion and contraction ot' said motor member so as to correspond with predetermined temperature changes, and means for increasing or decreasing the range of maximum movement of said lever member. 2'?. ln combination a chamber casing, a diaphragm inclosing said casing, a liquid occupying the space within said casing and diaphragm, a pivoted lever member adapted to be turned inward and outward` an intermediate member bearing on said diaphragm and also on said member near its pivot and on being moved outward bv the diaphragm turning the member outward. limiting means limiting the inward and outward movements of said intermediate member. means -for so adjusting the volume of said liquid that upon a predetermined rise of temperature said diaphragm moves said intermediate member to the outward limit permitted by said limiting means, and means upon a subsequent fall of temperature moving said lever member and intermediate member to the inward limit permitted by said limiting means. i

'28. ln combination a chamber casing, a diaphragm inclosing said casing, a. liquid occupying the space within said casing and diaphragm. a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing on said diaphragm.

and also on said member near its pivot and on being moved outward by the diaphragm turning the member outward. limiting means limiting the inward Land outward movements of said intermediate member, means for so adjusting the volume of said liquid that upon a predetermined rise of temperature said diaphragm moves said intermediate member to the outward limit permitted by said limiting means, means upon a subsequent fall of temperature moving said lever member and intermediate member to the inward limit permitted by said limiting means, and means for increasing 0r decreasing the range of maximum movement of said lever member.

29. In combination a chamber'casing havingtwo diaphragm openings, a motor diaphragm closing one of said openings, a relief diaphragm closing the other of said openings,V a liquid occupying the space within said casing and diaphragms, a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing on said motor diaphragm and also on said member near its pivot and on being moved outward by the motor diaphragm turning the member outward, limiting means limiting the inward and outward movements of said intermediate member, means for so adjusting the volume of said liquid that upon a predetermined rise of temperature Said motor diaphragm moves said intermediate member to the outward limit permitted by said limiting means, means upon a subsequent fall of temperature moving said lever member. andintermediate member to the inward limit permitted by said limiting means, and relief mechanism preventing an outward movement of said relief diaphragm until after a full outward movement of said motor diaphragm and then temporarily permitting such former movement.

30. In combination a chamber casing having two diaphragm openings, a motor diaphragm closing one of said openings, a relief diaphragm closing the other of said openings, a liquid occupying the space within said casing and diaphragms, a pivoted lever member adapted to be turned inward and outward, an intermediate member bearing on said motor diaphragm and also on said member near its pivot and on being moved outward by the motor diaphragm turning the memberoutward, limiting means limiting the inward and outward movements of said intermediate member,

means for so adjusting the volume of said liquid that upon a predetermined rise of temperature said motor diaphragm moves saidv intermediate member to the outward limit permitted by said limiting means, means upon a subsequent fall of temperature moving said lever member' and intermediate member to the inward limit permitted by said limiting means, relief mechanism preventing an outward movement of said` relief diaphragm until after a full outward movement of said motor diaphragm and then temporarily permitting such former movement, and means for increasing or decreasing the range of maximum movement of said lever member. f'

31. In combination a chamber casing structure having a diaphragm opening and adapted to be filled with a Huid under pressure, a diaphragm closing-said opening with its edges resting upon said structure, a reciprocating member resting on the central part of said diaphragm, means for forcing said member inward, limitin means limiting the inward movements of said member,

`and an outer casing surrounding the end of said member near said diaphragm and clamping the edges of the diaphragm to said structure, said outer casing having an annular concave formation between its clamping part and said member such that on an outward distending of the diaphragm and on a movement of the member to the outward limit permitted by said limiting means the diaphragm bears evenlyon the member and the concave formation.

32. In combination a chamber casing member, and an outer casing surrounding the end of said member near said diaphragm and clamping the edges ofthe diaphragm to said structure, said outer casing having an annular concave formationbetween its clamping part and said member such that on an outward distending of the diaphragm and on a movement of the member to the outward limit permitted by said limiting means the diaphragm bears evenly on the member and the adjacent concave formation. 33. In combination a liquid container, a pipe of less diameter than said container and at oneend connecting with it, a casing connecting with the other end .of said pipe, a diaphragm inclosing said casing, a` liquid occupyingthe space within said container, pipe, casing Aand diaphragm, movement multiplying mechanism in operative relation with said diaphragm, means operatmg on a predetermined rise of temperature about said container to permitfsaid diaphragm to move said mechanism a predetermined distance and upon a subsequent fall of such temperature to cause said mechanism to press upon and to follow said diaphragm back.to its initial position, and means operating in case of an excess of tem-Y perature about said container above such predetermined rise to permitI of a temporary expansion of a part of said caslng.

y FRANK N. ROEHRICH. Witnesses: l JOHN E. PRAGER, A.' WARDEN Grens. 

